Heat Treat FAIL !!!! Help !!!

Battle Creek Knives

Well-Known Member
Heat Treat FAIL !!!! *Update*

couple questions for you guys..

first off steel is 1095 and I just got a 50 RC test off one of 6 blades I HT'd yesterday..

I tempered at 400 2x2

What do I need to do in order to re heat treat the blade.. ?? must I anneal it or can I simply retreat??

I only had 2 blades tested as they were in my truck when I went by the RC guy, one tested at 58 its 1/8" thick, the other is 5/32 and tested at 50..

is it possible that after opening the kiln each time to get a blade (6 in all) it dropped its temp?? my garage is around 65degrees

if so, when HTing multiple blades do you have to wait a while between each blade??

good thing I have my blades tested before I try to sell them :eek:
 
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Ok, there could be a couple of things going on here but, to start with, you do not need to repeat annealing or normalizations. One problem is that 1095 can be very shallow hardening depending on the manganese level. You didn't say what you were quenching in but if it was something like vegetable oil you might have to go to something faster. You could try an oil designed for shallow hardening steels, such as Parks #50, or go to water or brine. The last two are very harsh quenchants and you will need to make sure that you have removed or reduced all stress risers possible. I would sand out to at least 220 grit before attempting to quench with either one.

Another problem is that the steel might not have been hot enough when it entered the quenchant. Have your quench tank close to your forge and try to get from the forge to the quenchant in about one second. You might also want to get the steel just a little brighter in the forge before quenching. Remember that steel becomes non-magnetic just before it changes phases so you need to have it a little hotter than that without going above upper critical temperature.

I don't think that your tempering temperature is the problem if that is what was measured with a thermometer. And yes, you are very right that there needs to be some testing of a blade for hardness before a handle is put on it. As far as how many blades can be heat treated at a time will depend on how well you quench tank maintains temperature. The quenchant will get hotter as you quech successive blades. Monitor the temperature with a thermometer and allow the quenchant to cool if it gets too hot.

Doug
 
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Hi Doug thanks for responding so quickly..

I was quenching in canola oil at 130* within the second, quench is right under kiln.. The local HT guy has some quench he'd let me try out a couple gallons for free, I'll have to ask the specs on it and see if its a fast quench.. they mainly do 01 parts, tools....

I will have the other blades tested later today or tomorrow, but I'm hoping this was maybe the last blade out of the kiln.. otherwise looks like I'll be doing them all over again..

I just thought about it and the blade that tested 58rc was 01, it was the only one in the batch so I just did it the same as the 1095..
 
Monitor the temperature with a thermometer and allow the quenchant to cool if it gets too hot.

I used a thermometer and I'm really hoping this is the case, I've only quenched up to 4 blades at a time with no issues... after the last blade I was moving my tank and pulled out the thermometer it read 150*:what!:

I wasn't paying attention to the temp as I wanted the blades out asap.. got all hyped about doing 6 blades and now apparently have to live and learn through another trial and error moment. :D
 
This situation sounds very familiar, and is one that I have received tons of emails and phone calls about. Frankly, my advice is to avoid using 1095. There are some batches of it that you have less than one second to get over the TT curve in order for it to fully harden. That's physically impossible for the majority of Knifemakers. I've not used, nor had any 1095 in the shop for about 3 years now.....I simply don't have the time to waste on it.
 
I fully agree with Ed Caffery. 1095 is a great steel, but is a little too demanding for beginners. I suspect you did not get the blades hot enough. Canola oil is a pretty good quench oil for 1095. About as good as it gets without going to Parks #50, which is probably the best oil made for it. As far as the one second rule of getting it in the quench, that is a common misunderstanding. The one second rule relates to the cooling speed of the quench oil. In order to attain full hardness, 1095 must drop in temp from about 1475° to under 900° in less than a second, but you will not lose enough heat to affect anything if moving from oven to quench in one swift motion that takes a little more than a second. Try a piece at 1475° with a ten minute soak, quench in the canola at 130°, and check it.
 
10 mins isn't to long?? I think I only went 5 on this one..

I'll do that with a scrap piece and see how it goes to get this dialed in, I have a slew of it so I'm stuck with 1095 for a long time...
 
The reason that I tell people to get the blade into the quenchant in about one second is different from the time it takes to beat the nose of the IT diagram, at least in a way. The reason that I say that is to make sure that the steel is still above lower critical temperature when it enters the quenchant. Depending on the manganese level you can have less than one second to cool the steel from lower critical temperature to below the temperature at the nose of the curve to avoid pearlite and bainite formation with 1095. I understand that Aldo Bruno at The New Jersey Steel Baron had a melt of 1095 made for him that had a higher manganese level. From what has been said around about 1095, his is the only 1095 that I would buy, if I was buying 1095. 1084 works good enough for me.

Doug
 
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that's Aldos steel I'm using..

I will update my findings when I bring the rest of the blades in to be tested and see how the rest of the blades fare in hardness....
 
You are not going to lose 60° of heat in the time it takes to bring a blade out of an oven and get it in the quench unless you move very slow, or have the quench too far away. It should be right at the oven, in a position that allows the quickest access to it, but to call one second a make or break, might be a bit over emphasized. As far as the problem that happened, I think there may be a piece of the puzzle missing. especially if that was Aldo's 1095.
 
Agreed, Aldo's 1095 was made for knife making. That would lead me to think that you are not getting your steel as hot as you think you are. Also you need to give it a soak at temperature for about 5 minutes to disolve the carbides, cementite included, and put adiquate carbon into solution. Try getting the steel just a little hotter and soak for fiive minutes at that temperature and then quench. Check the hardness of the blade with a file after taking it out of the quenchant. It should skate across the edge with doing anything more than bite just slightly into the decarb layer. I first ran into Aldo's 1095 at a hammer-in about 2 years ago and I recall that it did harden in vegetable oil.
 
1095 difficult to work with.... now you tell me! I just bought 60 lbs of it for pattern metal forging with 15N20. How will a 50/50 mix be to heat treat?

I was using 1084 and 15N20 with great success.

ernie
 
I would also agree with Ed. 1095 was hard for me to get consistent results, so I gave it up. On the other hand, I don't think canola works very well for it, not consistently anyway. I think that oil is much better suited for your O-1 (I usually get about 63Rc out of the quench with O-1 and canola). I bought some of the McMaster 11 sec oil (I think that is the name) to quench 1095 in and that did help out, although I am much more consistent with O-1.

Ultimately, find a steel that you get the most consistent HT'ing results with (with the equipment you have) and stick with it. I am not one to believe that you have to use a bunch of different steels. Get good with one, then move on if you want.
 
Ernie,

Depending on the particular batch of 1095 you got, it may either work fine, or it may cause you fits.....that's the problem with it. In the immortal words of Forrest Gump... 1095 is like a box of chocolates.....you never know what your gona to get. Hence the reason I will not use it.

At present I don't think you're going to find a better overall combination for damascus than 1080/1840 & 15N20. I've often used the term "compatible" to describe steels used in damascus....meaning that the steesl have very similar contraction, expansion, and working properties...and you can't get much more "compatible" than 1080/1084 & 15N20.
 
Ernie, about all I can say is to use it and see what comes of it. The various metal components of the steel bars aren't going to change much, if any. You will have bands of differing manganese levels and nickel through the billets. They don't diffuse much. The carbon will diffuse and will probably even out to about 80-85 points throughout depending on the actual carbon contents of the steels in the mix.

It might be worth while to invest in something like Parks #50 or cringe and use something like water or brine to speed the cooling.

Doug
 
It might be worth while to invest in something like Parks #50 or cringe and use something like water or brine to speed the cooling.

Doug
I agree 100%.
Also, I will only use 1095 purchased from Aldo... I've had similar results to Ed's with other supplier's steel. You could get lucky, but....
 
It seems there are more threads posted about getting 1095 heat treating down than most any other carbon steel. It's good steel that hold an edge but a bit fussy to get hard.
 
As far as a source of Parks #50 or another fast quenching oil, I would have to do a search myself. Maybe HighTemperature Tools and Refractory might have it. Water or brine the quenchant should be around 160 degrees and often some detergent is added to it. The times when I used brine it had as much salt in it as would disolve but later I ran across a recommendation of, I think, one cup of salt per gallon of water. Water is harsh and there is a vapor jacket that can cause uneven cooling. Brine is harsher but has less of a vapor jacket. There are smiths who use both and state that they don't have a lot of cracking or outright breaking. Maybe they stick to simpler steels and are real good at reducing or elliminating stress risers. Most of us who use or have used it cringe as we plung our blades in and hope that we don't hear the dreaded tink though you can hedge your bets by doing an interupted quench. In for three seconds, out for three seconds, repeat the cycle one more time then leave the steel in until it's at the same temperature as the quenchant.

Doug
 
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